Method and system for a fast cell recovery on suspended virtual modems within a multi-sim multi-standby communication device

ABSTRACT

A multiple-subscriber identity module (multi-SIM) multi-standby communication device comprises a single radio resource unit shared by a plurality of virtual modems (VMs). A first VM in an active state monitors its own associated cells and cells associated with remaining VMs in a suspended state. The active VM measures signal strength on available cells to track cell information such as cell quality and cell timing information for associated cells for the first active VM and for the remaining suspended VMs. When the suspended VMs are resumed, the single radio resource unit is synchronized to corresponding serving cells in an order determined based on the tracked cell timing information. With a synchronized serving cell, a suspended VM may bypass cell selection or reselection and directly camp on its serving cell. Otherwise, the suspended VM performs a cell selection or reselection selectively based on tracked cell information for a cell to camp on.

CROSS-REFERENCE TO RELATED APPLICATIONS/INCORPORATION BY REFERENCE

This patent application makes reference to, claims priority to and claims the benefit from U.S. Provisional Patent Application Ser. No. 61/261,922 filed on Nov. 17, 2009.

This application makes reference to:

-   -   U.S. application Ser. No. 12/816,782 filed on Jun. 16, 2010,     -   U.S. application Ser. No. 12/816,835 filed on Jun. 16, 2010,     -   U.S. application Ser. No. ______ (Attorney Docket No. 21191         US02) filed on even date herewith, and

U.S. application Ser. No. ______ (Attorney Docket No. 21193US02) filed on even date herewith.

Each of the above stated applications is hereby incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

Certain embodiments of the invention relate to communication systems. More specifically, certain embodiments of the invention relate to a method and system for a fast cell recovery on suspended virtual modems within a multi-SIM multi-standby communication device.

BACKGROUND OF THE INVENTION

With the development of mobile communication systems, mobile devices may utilize various mobile communication techniques such as, for example, global system for mobile communications (GSM), Universal Mobile Telecommunications System (UMTS), Long Term Evolution (LTE) network and wireless local area network (WLAN) to receive desired services. In instances where a mobile device subscribes to a communication network, subscriber information may be required to identify the mobile device to the network for various network services such as authentication, accounting, billing and security services. The subscriber information may be stored in a subscriber identity module (SIM) card inserted in the mobile device. A SIM card is a card or a chip installed in the mobile device providing information to identify the subscriber carrying the mobile device to networks.

Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of skill in the art, through comparison of such systems with some aspects of the present invention as set forth in the remainder of the present application with reference to the drawings.

BRIEF SUMMARY OF THE INVENTION

A method and/or system for a fast cell recovery on suspended virtual modems within a multi-SIM multi-standby communication device, substantially as shown in and/or described in connection with at least one of the figures, as set forth more completely in the claims.

These and other advantages, aspects and novel features of the present invention, as well as details of an illustrated embodiment thereof, will be more fully understood from the following description and drawings.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a diagram illustrating an exemplary communication system that is operable to support fast cell recovery for suspended virtual modems within a multi-SIM multi-standby communication device, in accordance with an embodiment of the invention.

FIG. 2 is a block diagram illustrating an exemplary multi-SIM multi-standby communication device that is operable to support a fast cell recovery for suspended virtual modems, in accordance with an embodiment of the invention.

FIG. 3 is a block diagram illustrating an exemplary multi-instance virtual modem approach to concurrently handle multi-instance tasks on a multi-SIM multi-standby communication device, in accordance with an embodiment of the invention.

FIG. 4 is a block diagram illustrating exemplary steps that may be performed by a multi-SIM multi-standby communication device to track serving cells and/or neighbor cells associated with virtual modems in a suspended state via a virtual modem in an active state, in accordance with an embodiment of the invention.

FIG. 5 is a flow chart illustrating exemplary steps that may be performed by a virtual modem in a suspended state for a fast cell recovery utilizing cell information tracked by a virtual modem in an active state, in accordance with an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Certain embodiments of the invention may be found in a method and system for a fast cell recovery on suspended virtual modems within a multi-SIM multi-standby communication device. In various embodiments of the invention, a multiple-subscriber identity module (multi-SIM) multi-standby communication device comprises a single radio resource unit providing open system interconnect (OS) layer 1, namely, physical layer (PHY), and RF, for example, functionalities. The single radio resource unit is shared by a plurality of virtual modems (VMs) implemented in a virtual modem architecture (VMA). The VMA is deployed on the single radio resource unit to handle operations in a multi-standby mode. The VMA comprises a plurality of virtual modems (VMs), a virtual modem framework (VMF) and a virtual modem controller (VMC). Each of the VMs is uniquely associated with a single one of a plurality of SIM cards that are coupled to the multi-SIM multi-standby communication device. Each of the VMs may operate in one of a plurality of VM states, comprising, for example, an active state, an idle state and a suspended state. In instances where a first VM is operating in an active state and one or more remaining ones of the plurality of VMs are operating in a suspended state, the first VM operating in the active state may be operable to monitor its own serving cell and/or one or more neighbor cells, and serving cells and/or neighbor cells associated with remaining ones of the plurality of VMs that are operating in the suspended state. In this regard, the serving cells and/or neighbor cells associated with the one or more remaining ones of the plurality of VMs that are operating in the suspended state may be added as neighbor cells for the first VM operating in the active state. Signal strength may be measured by the first VM operating in the active state on its own serving cell and/or one or more neighbor cells, and serving cells and/or neighbor cells associated with the one or more remaining ones of the plurality of VMs operating in the suspended state. The cell signal strength measurements may be utilized to determine cell quality of corresponding cells. Cell quality of a cell may be calculated or estimated utilizing received power information such as, for example, received power, signal-to-noise ratio (SNR) and/or signal-to-interference-noise ratio (SINR), of reference signals such as pilot signals and/or synchronization signals that are assigned by a network to the cell. The first VM operating in the active state may be operable to track cell information such as cell timing information for its own serving cell and/or one or more neighbor cells, and the added serving cells and/or neighbor cells associated with the one or more remaining ones of the plurality of VMs operating in the suspended state based on the corresponding cell signal strength measurements. The tracked cell information may be stored in a database to be shared by a plurality of VMs in the VMA for a fast cell recovery, for example. In instances where the first VM operating in the active state returns to an idle state, the one or more suspended VMs may resume normal idle mode operation. In this regard, the single radio resource unit may synchronize to the serving cells associated with the suspended VMs in an order that may be determined based on the tracked cell timing information. A suspended VM may bypass cell selection or reselection and directly camp on an associated serving cell if the associated serving cell is still synchronized. Otherwise, a cell selection or reselection may be selectively performed by the suspended VM based on the tracked cell information in order to quickly identify a suitable cell to camp on.

FIG. 1 is a diagram illustrating an exemplary communication system that is operable to support a fast cell recovery for suspended virtual modems within a multi-SIM multi-standby communication device, in accordance with an embodiment of the invention. Referring to FIG. 1, there is shown a communication system 100. The communication system 100 comprises a plurality of mobile devices 110, of which multi-SIM multi-standby communication devices 112-116 are illustrated, a UMTS network 130, a Long Term Evolution (LTE) network 140, and a GSM network 150.

A multi-SIM multi-standby communication device such as the multi-SIM multi-standby communication device 112 may comprise suitable logic, circuitry, interfaces and/or code that are operable to communicate or support various network services such as authentication, billing and/or security with a plurality of communication access networks such as, for example, the UMTS network 130, the LTE network 140, and the GSM network 150. Multiple SIM cards such as SIM cards 112 a may be inserted in the multi-SIM multi-standby communication device 112 whenever needed. The inserted SIM cards 112 a may be coupled or connected with the multi-SIM multi-standby communication device 112 through one or more SIM card sockets or connections. The multi-SIM multi-standby communication device 112 may read or retrieve SIM identification information from the SIM cards 112 a via the one or more SIM card sockets or connections. The retrieved SIM identification information may be stored within the multi-SIM multi-standby communication device 112 to support various network services such as authentication, billing and security whenever needed. In this regard, the multi-SIM multi-standby communication device 112 may be configured to activate the retrieved SIM identification information either on one SIM card at a time or on multiple SIM cards at the same time depending on implementation and/or device configuration. In instances where the retrieved SIM identification information is activated on one SIM card at a time, the multi-SIM multi-standby communication device 112 may operate in a single-standby mode. In instances where the retrieved SIM identification information is activated on two or more SIM cards at the same time, the multi-SIM multi-standby communication device 112 may operate in a multi-standby mode. In this regard, the multi-SIM multi-standby communication device 112 in a multi-standby mode may be operable to support multiple subscriptions at the same time. A user of the multi-SIM multi-standby communication device 112 may be allowed to utilize multiple numbers, multiple different service plans and/or one or more network carriers at the same time whenever the multi-SIM multi-standby communication device 112 is in a multi-standby mode. A single radio resource unit may comprise suitable logic, circuitry, interfaces and/or code that are operable to provide PHY and RF functionalities to support desired services on a communication device. For example, single radio resource unit 112 c-116 c may be integrated into the multi-SIM multi-standby communication devices 112-116, respectively, for PHY and RF support.

U.S. application Ser. No. 12/816,782, which is filed on June 16, 2010 provides detailed descriptions that a Virtual Modem Architecture (VMA) may be adopted over a single radio resource unit to support a multi-standby mode on a multi-SIM multi-standby communication device, and is hereby incorporated herein by reference in its entirety.

The multi-SIM multi-standby communication device 112 may deploy a VMA 112 b over the single radio resource unit 112 c to support operations in a multi-standby mode. The VMA 112 b may be configured to concurrently handle multiple tasks or instances over the single radio resource unit 112 c. Each task or instance is associated with one of the multiple SIM cards 112 a. A task may also be called an instance of a process. An air interface protocol stack and/or a Common Application Programming Interface (CAPI) module may comprise multiple tasks. A collection of air interface protocol stack tasks and/or CAPI tasks associated with a single SIM card together with appropriate physical layer (PHY), DSP functionalities, and/or RF functionalities supported by the single radio resource unit 112 c is referred to as a Virtual Modem (VM). Each VM in the VMA 112 b may be assigned to handle instances related to one of the multiple SIM cards 112 a. With regard to a particular VM in the VMA 112 b, a cell may act as a serving cell or a neighbor cell.

A cell comprises a geographical area covered or served by a base station. A serving cell for the particular VM is a cell that is served by a base station to which the particular VM currently camps on. One or more neighbor cells may be associated with the particular VM. A neighbor cell for the particular VM is a neighbor of the serving cell of the particular VM. A neighbor cell for the particular VM is served by a base station to which the particular VM does not currently camp on. Each of the VMs in the VMA 112 b may be assigned to handle instances related to one of the multiple SIM cards 112 a. A VM may be placed or may operate in one of a plurality of VM states, comprising, for example, an active state, an idle state or a suspended state. In an active state, radio resources are assigned to the VM and a valid or active connection between a VM and an associated cell is established for data and/or voice communication. The VM may be allowed to utilize radio resources available in the single radio resource unit 112 c to communicate or support services related to a specific SIM card. In an idle state, no valid or active connection between the VM and an associated cell is established; however, associated registration information is retained in the associated cell/network. In the idle state, the VM may be allowed to utilize limited radio resources available in the single radio resource unit 112 c to monitor paging events and to perform normal idle mode activities such as cell selection/reselection. In a suspended state, a VM may be totally suspended from using radio resources available in the single radio resource unit 112 c. Before entering the suspended state, the VM may need to suspend or abort procedures such as, for example, data transfer, operating band change and/or manual public land mobile network (PLMN) search, which are currently being executed on the VM.

The VMA 112 b may be operable to arbitrate and/or resolve contention for radio resources via the transition of the VM among one or more of the three VM states. For example, the VMA 112 b may ensure that at most one of the plurality of VMs in the VMA 112 b is in the active state for a given time instant. In other words, no two or more VMs may be allowed to be in an active state at the same time. In this regard, the VMA 112 b may be operable to suspend one or more of the plurality of VMs from using or sharing radio resources available in the single radio resource unit 112 c to ensure an uninterrupted radio resource usage by a VM in an active state.

In various exemplary embodiments of the invention, serving cells and/or neighbor associated with the one or more VMs in a suspended state may be added as neighbor cells for the VM in the active state. In other words, the VM in the active state may be operable to monitor its own serving cell and/or one or more neighbor cells, and serving cells and/or neighbor cells associated with the one or more VMs in the suspended state. In this regard, the VM in the active state may be operable to measure signal strength on its own serving cell and/or one or more neighbor cells, and each of serving cells and/or neighbor cells associated with one of the VMs in the suspended state. In addition to the cell signal strength measurement, the VM in the active state may also track other cell information such as, for example, associated cellular frequencies, cells placed on particular cellular frequencies, and/or cell identities, for each of serving cells and/or neighbor cells associated with one of the VMs in the suspended state. The resulting cell signal strength measurements may indicate cell quality information. For example, a cell corresponding to the strongest cell signal strength measurement may be selected or utilized to support cell timing tracking performance, when needed. The VM in the active state may track or retrieve cell information such as cell timing information for its own serving cell, and serving and/or neighbor cells associated with the VMs in the suspended state based on the cell signal strength measurements. The tracked cell information such as, for example, cell measurements, cell timing information, associated cellular frequencies, possible cells on particular cellular frequencies and/or corresponding cell identities, may be shared among the VMs in the VMA. In this regard, the cell search time may be reduced for each of the VMs. Cell search results for a particular VM may be shared or utilized by other VMs for a fast cell recovery and/or for other procedures such as PLMN search and/or user selection of a particular PLMN.

In various exemplary embodiments of the invention, the retrieved cell timing information for serving and/or neighbor cells associated with the VMs in the suspended state may be utilized for a fast cell recovery on corresponding VMs in the suspended state. For example, after the VM in the active state returns to an idle state, a VM in the suspended state may be resumed for normal idle activities. In instances where a serving cell associated with the VM in the suspended state is still synchronized, the VM in the suspended state may directly camp on the associated serving cell for normal idle mode activities without performing cell selection or reselection. In instances where a serving cell associated with the VM in the suspended state is not synchronized, the VM in the suspended state may selectively perform cell selection/reselection based on tracked cell information such as cell signal strength measurements, cell timing information, cells on particular cellular frequencies and/or cell identity information. For example, the VM in the suspended state may perform cell selection/reselection for cells with high cell quality and/or for cells on particular cellular frequencies.

In various exemplary embodiments of the invention, the retrieved cell timing information may be utilized by the single radio resource unit 112 c to arbitrate or resolve cell scheduling conflicts. For example, the single radio resource unit 112 c may synchronize to cells in an order that is based on corresponding cell timing information so as to avoid scheduling conflicts.

The UMTS network 130 may comprise suitable devices, circuitry, interfaces and/or code that are operable to provide data and/or voice services to various UMTS capable communication devices such as the multi-SIM multi-standby communication device 112 using UMTS technology. In this regard, the UMTS network 130 may be operable to authenticate users such as the multi-SIM multi-standby communication devices 112-116 for UMTS access utilizing SIM cards. A SIM card for UMTS is also known as universal subscribe identity module (USIM). Only authorized users may access the UMTS network 130. The UMTS network 130 may be operable to check the validity of USIM identification information on one or more USIM cards coupled to, for example, the multi-SIM multi-standby communication device 112. The UMTS network 130 may determine whether the multi-standby communication device 112 is allowed to access the UMTS network 130 for various network services such as, for example, authentication, accounting and/or billing services. The UMTS network 130 may comprise a plurality of base stations such as base stations 130 a-130 c to communicate with associated communication device such as the multi-standby communication device 112.

The LTE network 140 may comprise suitable devices, circuitry, interfaces and/or code that are operable to provide data and/or voice services to various LTE capable communication devices such as the multi-SIM multi-standby communication device 112 using LTE technology. In this regard, the LTE network 140 may be operable to authenticate users such as the multi-SIM multi-standby communication devices 112-116 for LTE access utilizing SIM cards. A SIM card for LTE is also known as Universal Integrated Circuit Card (UICC). Only authorized users may access the LTE network 140. The LTE network 140 may be operable to check the validity of UICC identification information on one or more UICCs coupled to, for example, the multi-SIM multi-standby communication device 112. The LTE network 140 may determine whether the multi-SIM multi-standby communication device 112 is allowed to access the LTE network 140 for various network services such as, for example, authentication, accounting and/or billing services. The LTE network 140 may comprise a plurality of base stations such as base stations 140 a-140 c to communicate with associated communication device such as the multi-standby communication device 112.

The GSM network 150 may comprise suitable devices, circuitry, interfaces and/or code that are operable to provide data and/or voice services to various GSM capable communication devices such as the multi-SIM multi-standby communication device 112 using GSM technology. In this regard, the GSM network 150 may be operable to authenticate users such as the multi-SIM multi-standby communication devices 112-116 for GSM access utilizing SIM cards. Only authorized users may access the GSM network 150. The GSM network 150 may be operable to check the validity of SIM identification information on one or more SIM cards coupled to, for example, the multi-SIM multi-standby communication device 112. The GSM network 150 may determine whether the multi-SIM multi-standby communication device 112 is allowed to access the GSM network 150 for various network services such as, for example, authentication, accounting and/or billing services. The GSM network 150 may comprise a plurality of base stations such as base stations 150 a-150 c to communicate with associated communication device such as the multi-standby communication device 112.

A base station may comprise suitable logic, circuitry, interfaces and/or code that are operable to manage and schedule communication resources in an uplink direction and/or downlink direction within a served geographic area, namely, a cell. The base station may be operable to receive and/or transmit radio frequency signals from and/or to communication devices such as the multi-standby communication device 112-116 using various air interface protocols. For example, the base stations 130 a-130 c, the base stations 140 a-140 c and the base stations 150 a-150 c may be operable to utilize air interface protocols specified in the UMTS network 130, the LTE network 140 and the GSM network 150, respectively, to communicate with the multi-standby communication device 112-116.

In an exemplary operation, a multi-SIM multi-standby communication device such as the multi-SIM multi-standby communication device 112 may be connected or coupled with multiple SIM cards such as the SIM cards 112 a through one or more SIM card sockets or connections. SIM identification information on the multiple SIM cards may be utilized on one SIM card at a time and/or on multiple SIM cards at the same time depending on implementation. SIM identification information on each of the multiple SIM cards 112 a may be communicated to the multi-SIM multi-standby communication device 112 through the one or more SIM card sockets. The multi-SIM multi-standby communication device 112 may operate in a single-standby mode or a multi-standby mode depending on device configuration and/or user preferences. A user of the multi-SIM multi-standby communication device 112 in a multi-standby mode may be allowed to utilize SIM identification information associated with each of the multiple SIM cards 112 a to receive corresponding services at the same time.

In an exemplary embodiment of the invention, multiple numbers, multiple different service plans and/or one or more network carriers associated with each of the multiple SIM cards 112 a may be utilized at the same time on the multi-SIM multi-standby communication device 112. In this regard, the multi-SIM multi-standby communication device 112 may be operable to utilize the VMA 112 b over the single radio resource unit 112 c to support a multi-standby mode. The VMA 112 b may be operable to receive services associated with the multiple SIM cards 112 a at the same time. Each VM in the VMA 112 b is assigned to serve one of the multiple SIM cards 112 a. For a given time instant, a VM may be in one of the three VM states, namely, an active state, an idle stat and a suspended state. The VMA 112 b may be configured to manage contention from associated VMs for radio resources available in the single radio resource unit 112 c. For example, the VMA 112 b may be operable to suspend one or more VMs from using radio resources available in the single radio resource unit 112 c to ensure an uninterrupted radio resource usage by a VM in an active state. In this regard, serving cells and/or neighbor cells associated with the VMs in a suspended state may be added as neighbor cells for the VM in the active state. The VM in the active state may be configured to measure signal strength on its own serving cell and/or one or more neighbor cells, and serving cells and/or neighbor cells associated with each of the VMs in the suspended state. Cell information such as cell timing information, associated cellular frequencies and/or cell identity information may be tracked by the VM in the active state for its own serving cell and/or one or more neighbor cells, and serving cells and/or neighbor cells associated with the VMs in the suspended state based on the corresponding cell signal strength measurements. The retrieved cell information may enable a fast cell recovery on the VM in the suspended state, whenever needed. Furthermore, to avoid cell scheduling conflicts, the single radio resource unit 112 c may manage operations of the VMs in the VMA 112 b to quickly synchronize to related cells based on the retrieved cell timing information.

FIG. 2 is a block diagram illustrating an exemplary multi-SIM multi-standby communication device that is operable to support a fast cell recovery for suspended virtual modems, in accordance with an embodiment of the invention. Referring to FIG. 2, there is shown a multi-SIM multi-standby communication device 200. The multi-SIM multi-standby communication device 200 comprises a wireless radio unit 202, a user interface unit 204, a processor unit 206, a SIM card controller 208 comprising SIM card sockets 208 a-208 c, a plurality of SIM cards, of which SIM cards 212-222 are illustrated, and a memory 220. The SIM cards 212-222 are coupled to the multi-SIM multi-standby communication device through the SIM card sockets 208 a-208 c. The memory 220 comprises a SIM database 220 a and a cell database 220 b.

The wireless radio unit 202 may comprise suitable logic, circuitry, interfaces and/or code that may be operable to synchronize to various communication networks such as, for example, the LTE network 140 and the GSM network 150, to communicate radio frequency signals. SIM identification information that is retrieved from one or more of the SIM cards 222-228 may be communicated via the wireless radio unit 202 to identify the multi-SIM multi-standby communication device 200 to network for desired network services such as accounting/billing services.

The user interface unit 204 may comprise suitable logic, circuitry, interfaces and/or code that may enable a user to interact with the multi-SIM multi-standby communication device 200. For example, the user interface unit 204 may be operable to present the user with information on SIM cards available to the multi-SIM multi-standby communication device 200. The user interface unit 204 may allow the user to enter a preferred SIM card selection and/or a desired application selection.

The processor unit 206 may comprise suitable logic, circuitry, interfaces and/or code that may be operable to manage and/or control operations of device components such as, for example, the wireless radio unit 202, the user interface unit 204, the SIM database 220 a, and/or the SIM card controller 208. For example, the processor unit 206 may be operable to coordinate and/or control operations of the SIM card controller 208 in response to a SIM card selection from the user interface unit 204. The processor unit 206 may also be operable to run a specific application via the application processor based on an application selection from the user interface unit 204.

The processor unit 206 may be operable to select one or more SIM cards based on user preferences and/or device configuration. The processor unit 206 may communicate the SIM card selection information to the SIM card controller 208 so that the selected one or more SIM cards may be connected to the SIM card sockets 208 a-208 c, which are directly coupled with the processor unit 206. The selected SIM cards may be actively connected to the SIM card controller 208 to enable downloading of corresponding SIM identification information into the SIM database 220 a of the multi-SIM multi-standby communication device 200. Notwithstanding, in accordance with various embodiments of the invention, after SIM identification information is downloaded from each of the selected SIM cards such as the SIM cards 212-222 into the SIM database 220 a of the multi-SIM multi-standby communication device 200, the SIM identification information corresponding to one or more of the plurality of SIM cards may be in an active state or in a standby state in the SIM database 220 a. More specifically, at a given time instant, SIM identification information actually being utilized or applied to access corresponding services by the multi-SIM multi-standby communication device 200 is in an active state, otherwise, in a standby state.

In instances where the multi-SIM multi-standby communication device 200 is configured to operate in a single-standby mode, the processor unit 206 may communicate with the SIM database 220 a to activate the stored SIM identification information related to one SIM card at a time. In other words, the multi-SIM multi-standby communication device 200, in a single-standby mode, may be operable to utilize SIM identification information activated for a single SIM card at a time. In instances where the multi-SIM multi-standby communication device 200 is configured to operate in a multi-standby mode, the processor unit 206 may be operable to communicate with the SIM database 220 a to activate the stored SIM identification information corresponding to multiple SIM cards such as the SIM cards 212-222 at the same time. Specifically, the multi-SIM multi-standby communication device 200, in a multi-standby mode, may be operable to utilize SIM identification information activated for multiple SIM cards at the same time. In this regard, the processor unit 206 may be operable to allow a user of the multi-SIM multi-standby communication device 200 to utilize SIM identification information associated with each of the SIM cards 212-222 to receive corresponding services at the same time. For example, the user may therefore be allowed to utilize multiple numbers, multiple different service plans and/or network carriers associated with each of the multiple SIM cards 212-222 at the same time on the multi-SIM multi-standby communication device 200. The processor unit 206 comprises a communication processor 206 a and an application processor 206 b.

The communication processor 206 a may comprise suitable logic, circuitry, interfaces and/or code that may be operable to utilize a VMA 206 c over a single radio resource unit such as the single radio resource unit 112 c associated with the wireless radio unit 202 to support a multi-standby mode. The VMA 206 c is a multi-SIM multi-standby platform and comprises a virtual modem controller (VMC), a Virtual Model Framework (VMF) and a plurality of VMs. Each VM in the VMA 206 c is assigned or related to one of the multiple SIM cards 212-222. For a given time instant, a VM may operate in one of a plurality of VM states, namely, an active state, an idle state or a suspended state. To avoid radio resource conflicts, at most one of the VMs in the VMA 206 c may be in an active state to transmit and/or receive traffic related to a corresponding SIM card. One or more VMs may be in an idle state at the same time depending on radio resources available in the single radio resource unit 112 c for sharing. One or more VMs may be in a suspended state at the same time.

In various exemplary embodiments of the invention, the VMA 206 c may be configured to add serving cells and/or neighbor cells associated with the one or more VMs in the suspended state as neighbor cells for the VM in the active state. The VM in the active state may be operable to monitor its own serving cell and/or one or more neighbor cells, and serving cells and/or neighbor cells associated with the one or more VMs in the suspended state. In this regard, the VM in the active state may be operable to measure signal strength on its own serving cell and/or one or more neighbor cells, and serving cells and/or neighbor cells associated with the VMs in the suspended state. The VM in the active state may also monitor or track other cell related information such as, for example, cell timing information, associated cellular frequencies associated, and/or corresponding cell identities, for each of serving cells and neighbor cells associated with the one of the VMs in the suspended state. Cell quality may be determined or identified based on the corresponding cell signal strength measurements. A cell with the strongest cell signal strength measurements may be selected or utilized to support or enhance cell timing tracking. The VM in the active state may be operable to track cell timing information for each available cell based on corresponding cell measurements. The cell signal strength measurements together with other cell information such as cell timing information, associated cellular frequencies, and/or cell identities may be stored in the cell database 220 b where it may be shared by multiple VMs in the VMA 206 c.

In various exemplary embodiments of the invention, the VMA 206 c may be operable to utilize the tracked cell information to support a fast cell recovery on VMs in the suspended state. For example, in instances where a VM in a suspended state is resumed from the suspended state to an idle state for normal idle activities, with a synchronized serving cell, the VM in the suspended state may be operable to directly camp on its own serving cell without performing cell selection or cell reselection. In instances where a serving cell for the VM in the suspended state is not synchronized, a cell selection/reselection may be selectively performed by the VM in the suspended state utilizing the cell information such as cell measurements, cell timing information, associated cellular frequencies and/or cell identities stored in the cell database 220 b. The resulting cell search results may be stored in the cell database 220 b to be shared or utilized by other VMs for a fast cell recovery and/or other purposes such as PLMN search, when needed.

In various exemplary embodiments of the invention, the VMA 206 c may be operable to communicate the tracked cell timing information with the single radio resource unit 112 c to support cell scheduling. For example, the single radio resource unit 112 c may be operable to determine a cell scheduling order for cell synchronization based on the tracked cell timing information. The cell scheduling order may comprise information such as when to synchronize to which cell in order to transmit and/or receive traffic related to a specific SIM card such as the SIM card 212. The communication processor 206 a may communicate the received data and/or voice traffic related to the SIM card 212 to the application processor 206 b to support desired applications.

The application processor 206 b may comprise suitable logic, circuitry, interfaces and/or code that may be operable to run various applications such as video and/or audio multimedia applications based on data and/or voice traffic received by the communication processor 206 a. The application processor 206 b may present applications to users through the user interface unit 204.

The SIM card controller 208 may comprise suitable logic, circuitry, interfaces and/or code that may be operable to manage and/or control connections from multiple SIM cards such as the SIM cards 212-222 to the SIM card sockets 208 a-208 c, which are directly coupled with the processor unit 206. In this regard, the SIM card controller 208 may be operable to establish connections between the SIM cards 212-222 and the processor unit 206. The SIM card controller 208 may be configured to switch SIM card connection from one to another as needed without re-booting the multi-SIM multi-standby communication device 200.

A SIM card such as the SIM card 214 may comprise suitable logic, circuitry, interfaces and/or code that may be operable to store subscriber personal identification information such as, for example, operator network, phone number, activated services, billing, and credit information. The SIM card 214 may also store the user's identity for gaining access to the network and receiving calls, and user's personal information such as phone directory and received SMS messages. The SIM card 214 may be implemented as a small printed circuit board. The SIM card 214 may be inserted in a mobile device such as the multi-SIM multi-standby communication device 200 in order for the multi-SIM multi-standby communication device 200 to properly access a corresponding network. The SIM card 214 may be connected to the multi-SIM multi-standby communication device 200 via the SIM card controller 208.

The memory 220 may comprise suitable logic, circuitry, interfaces and/or code that may be operable to store information such as executable instructions and data that may be utilized by the processor unit 206 and/or other device components such as, for example, the SIM database 208 a. The SIM database 208 a may comprise suitable logic, circuitry, interfaces and/or code that may be operable to record and/or store SIM identification information retrieved from one or more SIM cards such as the SIM cards 212-222. The stored SIM identification information may be in an active state or in a standby state within the SIM database 220 a. For a given time instant, only SIM identification information in an active state may be actually utilized or applied by the multi-SIM multi-standby communication device 200 to support desired network services such as accounting/billing services. Depending on device configuration, for a given time instant, SIM identification information in an active state may correspond to one or more SIM cards. The cell database 220 b may comprise suitable logic, circuitry, interfaces and/or code that may be operable to record and/or store cell information such as, for example, cell measurements, cell timing information, associated cellular frequencies, cell identities, cell selection results by one or more VMs in the VMA 206 c. The memory 220 may comprise RAM, ROM, low latency nonvolatile memory such as flash memory and/or other suitable electronic data storage.

In an exemplary operation, a multi-SIM multi-standby communication device such as the multi-SIM multi-standby communication device 200 may be connected or coupled to multiple SIM cards such as the SIM cards 212-222 through the SIM card controller 208. The processor unit 206 may be operable to retrieve SIM identification information from the SIM cards 212-222. The retrieved SIM identification information may be stored in the SIM database 220 a. In instances where the multi-SIM multi-standby communication device 200 is configured to operate in a multi-standby mode, the communication processor 206 a may communicate with the SIM database 220 a to activate the stored SIM identification information corresponding to multiple SIM cards such as the SIM cards 212-222 at the same time. More specifically, the multi-SIM multi-standby communication device 200, in a multi-standby mode, may utilize SIM identification information activated for the SIM cards 212-222 at the same time. A user of the multi-SIM multi-standby communication device 200 may therefore be allowed to receive data and/or voice services related to the SIM cards 212-222 at the same time. The communication processor 206 a may run the VMA 206 c over the single radio resource unit 112 c to handle data and/or voice traffic through the wireless radio unit 202. Radio resources available in the single radio resource unit 112 c may be shared among the VMs in the VMA 206 c. At most one of the VMs may be scheduled in the active state to transmit and/or receive data and/or voice traffic related to a corresponding SIM card. The VMA 206 c may be configured to suspend one or more VMs to ensure an uninterrupted radio resource usage by a VM in an active state. The VM in the active state may be operable to monitor its own serving cell and/or one or more neighbor cells, and serving cells and/or neighbor cells associated with the VMs in a suspended state. Serving cells and/or neighbor cells associated with the VMs in the suspended may be added as neighbor cells for the VM in the active state. The VM in the active state may measure signal strength on its own serving cell and/or one or more neighbor cells, and serving cells and/or neighbor cells associated with the VMs in the suspended state. The VM in the active state may also track other cell related information such as, for example, cell timing information, associated cellular frequencies, cell identity information and/or cell selection results for each of the serving cells and/or the neighbor cells associated with the VMs in the suspended state. For example, the VM in the active state may be operable to track cell timing information for its own serving cell and serving cells associated with the VMs in the suspended state based on the corresponding cell signal strength measurements. A fast cell recovery may be achieved on the VMs in the suspended state based on the tracked cell timing information, without performing cell selection or cell reselection. Furthermore, the VMA 206 c may coordinate or communicate with the single radio resource unit 112 c to be synchronized to cells in an order indicated by corresponding cell timing information so as to receive data and/or voice traffic related to specific SIM cards such as the SIM card 212. The communication processor 206 a may communicate the received data and/or voice traffic to the application processor 206 b. The application processor 206 b may be operable to run various applications such as video and/or audio multimedia applications according to the received data and/or voice traffic and present to users through the user interface unit 204.

FIG. 3 is a block diagram illustrating an exemplary multi-instance virtual modem approach to concurrently handle multi-instance tasks on a multi-SIM multi-standby communication device, in accordance with an embodiment of the invention. Referring to FIG. 3, there is shown virtual modem architecture 300 utilized on the multi-SIM multi-standby communication device 200, for example. The virtual modem architecture 300 comprises man-machine interface (MMI) module 310, a SIMIO module 320, a virtual modem framework (VMF) 330, a virtual modem controller (VMC) 360, and a single radio resource unit 370.

The MMI module 310 may comprise suitable logic, interfaces and/or code that may be operable to provide interaction between a user of the multi-SIM multi-standby communication device 200 and one or more applications that are executed on the multi-SIM multi-standby communication device 200.

The SIMIO module 320 may comprise suitable logic, interfaces and/or code that may be operable to manage access to SIM cards such as the SIM cards 212-222.

The VMF 330 may comprise suitable logic, interfaces and/or code that may be operable to provide an enhancement to the Real Time Operating System. The VMF 330 may be deployed or implemented on the communications processor 206 a.

A VM such as the VM 340 refers to an instance of an air interface protocol stack and/or its interface to the user, namely, a Common Application Programming Interface (CAPI), together with a single set of radio resources such as radio resources available in the single radio resource unit 370. A VM such as the VM 340 may comprise suitable logic, interfaces and/or code that may be operable to handle instances, namely, CAPI tasks and/or air interface protocol stack instances, associated with one of the SIM cards 212-222. Different VMs such as the VM 340 and the VM 350 may be configured to handle instances corresponding to two different SIM cards. For example, the VM 340 may handle instances related to the SIM card 212, while the VM 350 may be assigned to handle instances related to the SIM card 214. The plurality of VMs such as VMs 340-350 may be configured to share the same set of radio resources, namely, available radio resources in the single radio resource unit 370. In this regard, multiple copies of global and static data may be maintained to be utilized by the VMs 340-350, respectively. A VM such as the VM 340 may operate independently from other VMs and may be in one of the plurality of VM states, namely, an active state, an idle state and a suspended state. The VM 340 may comprise a CAPI task unit 342, a VCC 344, an air interface protocol stack 346 together with the single radio resource unit 370. CAPI and/or stack operations within the VM 340 may be managed via the VCC 344.

The CAPI task unit 342 may comprise suitable logic, interfaces and/or code that may be operable to process MMI or user requests. The CAPI task unit 342 comprises CAPI tasks related to a specific SIM card such as the SIM card 212.

A VCC such as the VCC 344 may comprise suitable logic, interfaces and/or code that may be operable to perform admission control with the VMC 360 for the CAPI module 315 at the primitive levels. The VCC 344 is a dual-instance module for managing its own task or instance, and queuing messages. The VCC 344 may be operable to interact with the VMC 360 for radio resource requests associated with CAPI tasks in the CAPI task unit 342. The VCC 344 may communicate with the air interface protocol stack 346 to coordinate stack operations corresponding to the CAPI tasks in the CAPI task unit 342.

An air interface protocol stack such as the air interface protocol stack 346 may comprise suitable logic, interfaces and/or code that may be operable to provide air interface protocols to support various signaling operations. For example, in 3GPP standard, the stack 346 may comprise Non-Access-Stratum (NAS) protocols and Access-Stratum (AS) protocols to handle bearer level signaling and Radio Resource Control (RRC) signaling, respectively.

The VMC 360 may comprise suitable logic, interfaces and/or code that may be operable to coordinate requests for the usage of radio resources available in the single radio resource unit 370 among multiple associated VMs such as the VM 340 and the VM 350. In this regard, the VMC 360 may be operable to resolve contention for radio resources by transitioning the VM 340 and the VM 350 between the three VM states. For example, the VMC 360 may be operable to ensure that at most one of the VM 340 and the VM 350 is in the active state for a given time instant. In this regard, the VMC 360 may suspend, for example, the VM 350 from using or sharing radio resources available in the single radio resource unit 370 in order to allow an uninterrupted radio resource usage by the VM 340. The suspended VM 350 may be resumed whenever radio resources in the single radio resource unit 370 become available for sharing by the VM 350 to continue idle mode activities on the VM 350.

The VMC 360 may be operable to coordinate the usage of the radio resources to support concurrent procedures initiated by the VM 340 and the VM 350. For example, the VM 340 and the VM 350 each may be granted by the VMC 360 a portion of radio resources available in the single radio resource unit 370 to concurrently monitor paging events and/or to concurrently perform idle mode procedures or activities such as, for example, cell selection/reselection by sharing the single radio resource unit 370.

The single radio resource unit 370 may comprise suitable logic, interfaces and/or code that may be operable to provide PHY and RF support.

In an exemplary operation, the MMI module 310 may interact between a user of the multi-SIM multi-standby communication device 200 and applications that are related to the SIM card 212 and the SIM card 214, for example, inserted into the SIM card controller 208. Tasks or instances related to the SIM card 212 and the SIM card 214 may be handled by the VM 340 and the VM 350, respectively. The VMC 360 may coordinate the usage of radio resources available in the single radio resource unit 370 for sharing by the VM 340 and the VM 350. For a given time instant, at most one of the VM 340 and the VM 350 may be allowed to use the single radio resource unit 370. In other words, for a given time instant, at most one of the VM 340 and the VM 350 may operate in an active state to transmit and/or receive traffic related to a corresponding SIM card. The VM 340 and/or the VM 350 may be in an idle state whenever there is no intended traffic for corresponding SIM cards detected. In an idle state, the VM 340 and the VM 350 may be operable to concurrently perform paging monitoring and/or idle mode procedures such as cell reselecting by sharing radio resources available in the single radio resource unit 370. For example, a VM such as the VM 340 in the idle state may be operable to check or detect an incoming traffic related to the SIM card 212 based on received paging messages. Upon detection of an intended traffic related to the SIM card 212, the VM 340 may remain in the idle state if traffic related to other SIM cards such as the SIM card 214 is still being handled. Otherwise, the VMC 360 may transition the VM 340 from the idle state to an active state in order to transmit and/or receive the detected traffic related to the SIM card 212.

FIG. 4 is a block diagram illustrating exemplary steps that may be performed by a multi-SIM multi-standby communication device to track serving cells and/or neighbor cells associated with virtual modems in a suspended state via a virtual modem in an active state, in accordance with an embodiment of the invention. Referring to FIG. 4, the exemplary steps may start with step 402. In step 402, VMs such as the VM 340 and the VM 350 in the VMA 112 b may be operating in an idle state. In step 404, the VM 340 and the VM 350 are concurrently monitoring paging events so as to check or detect intended traffic related to, for example, the SIM card 212 and the SIM card 214, respectively. In instances where an intended traffic related to the SIM card 212 is detected, the VM 340 may need to transition to an active state in order to transmit and/or receive the detected intended traffic. The VM 340 may communicate with the VMC 360 so as to indicate or signal the single radio resource unit 370 that the VM 340 should transition from the idle state to the active state. In order to guarantee the availability of radio resources by the VM 340 while it is in the active state, the VMC 360 may suspend other counterpart VMs such as the VM 350 in the VMF 330 in order to bar them from utilizing radio resources available in the single radio resource unit 370. The VMC 360 may indicate or signal the single radio resource unit 370 that the VM 350 needs to transition from the idle state to the suspended state. In step 406, the single radio resource unit 370 may be operable to terminate active events related to the VM 350 and release radio resources that were previously assigned to the VM 350 if any.

In step 408, the VMA 112 b may be operable to add serving cells and/or neighbor cells associated with the virtual modems to be suspended, for example, the VM 350, as neighbor cells for the virtual modem to be activated such as the VM 240. In step 410, the VMA 112 b may be operable to transition the VM 340 and the VM 350 from the idle state to the active state and the suspended state, respectively. In step 412, the single radio resource unit 370 may be operable to monitor a serving cell associated with the VM 340 as well as serving cells and/or neighbor cells associated with the virtual modems in the suspended state, for example, the VM 350. More specifically, the VM 340 may be operable to measure signal strength on its own serving cell and/or one or more neighbor cells, and the serving cell and/or the neighbor cells associated with the VM 350. Other cell related information such as, for example, associated cellular frequencies, cell identity information and/or cell selection results for each of the serving cells and/or neighbor cells associated with the VMs in the suspended state may be monitored or tracked by the VM in the active state. For example, cell timing information may be tracked based on the corresponding cell signal strength measurements. The tracked cell information may be stored into the cell database 220 b where it may be shared among VMs in the VMA 112 b for a fast cell selection/reselection.

In step 414, upon the completion of the communication on the detected intended traffic related to the SIM card 212, the VMA 112 b may determine whether the VM 340 should return to the idle state. In instances where the VM 340 needs to return to the idle state from the active state, the, in step 418, the single radio resource unit 370 may be operable to release radio resources previously allocated on the VM 340. In step 418, the single radio resource unit 370 may be operable to provide the cell information tracked by the VM 340 to the suspended VMs such as the VM 350 for a fast cell recovery on the VM 350. The exemplary steps may end in step 420.

In step 414, in instances where the VM 340 does not need to return to the idle state from the active state, the exemplary steps may return to step 412.

FIG. 5 is a flow chart illustrating exemplary steps that may be performed by a virtual modem in a suspended state for a fast cell recovery utilizing cell information tracked by a virtual modem in an active state, in accordance with an embodiment of the invention. Referring to FIG. 5, the exemplary steps may start with step 502. In step 502, a VM such as the VM 350 in a suspended state may be signaled by the VMC 360 to return from the suspended state to an idle state for resuming normal idle mode activities. In step 504, the VM 350 may determine whether to transition to the idle state. In instances where the VM 350 need to transition from the suspended state to the idle state, then in step 506, the VM 350 may inform the VMC 360 that the VM 350 needs to transition from the suspended state to the idle state, so that it may operate in normal idle mode and perform normal idle mode activities. The VM 350 then may receive cell information that is tracked by a last VM in the active state, for example, the VM 340.

In step 508, the VM 350 may be operable to determine whether a serving cell associated with the VM 350 is still available or synchronized. In instances where the serving cell associated with the VM 350 is synchronized, then in step 510, the single radio resource unit 370 may directly camp on the serving cell associated with the VM 350 without performing cell selection or reselection to achieve a fast cell recovery. The exemplary steps may end in step 516. In step 504, in instances where it is determined that the VM 350 should not transition from the suspended state to the idle state, then the exemplary steps stay in step 504.

In step 508, in instances where the serving cell associated with the VM 350 is not synchronized, then in step 512, the single radio resource unit 370 may be operable to initiate a cell selection or reselection process for the VM 350 so as to determine a suitable cell to camp on. In this regard, the VM 350 may be operable to communicate with the cell database 220 b to selectively perform cell selection or reselection based on the tracked cell information such as cell measurements, associated cellular frequencies, cell identities and corresponding cell timing information. For example, the VM 350 may be configured to perform cell selection/reselection only for cells with high cell quality and/or for cells placed on particular cellular frequencies. In step 514, the VM 350 may be operable to resume normal idle mode activities or procedures on the selected cell. The exemplary steps may end in step 516.

In various exemplary aspects of the method and system for a fast cell recovery on suspended virtual modems within a multi-SIM multi-standby communication device, a multi-SIM and multi-standby communication device such as the multi-SIM multi-standby communication device 200 comprises a single radio resource unit such as the single radio resource unit 370. The single radio resource unit 370 provides PHY, DSP and/or RF functionalities that may be shared by a plurality of VMs such as the VM 340 and the VM 350 in the VMA 112 b, a platform deployed over the single radio resource unit 370. Each of the VMs in the VMA 112 b is uniquely associated with a single one of a plurality of SIM cards such as the SIM cards 212-222 that are coupled to the multi-SIM multi-standby communication device 200 through the SIM card controller 208. Each of the VMs may operate in one of a plurality of VM states, namely, an active state, an idle state and a suspended state. In instances where a first VM such as the VM 340 is operating in an active state and one or more remaining ones of the plurality of VMs, for example, the VM 350, in the VMA 112 b are operating in a suspended state, the VM 340 in the active state may be operable to monitor its own serving cell and/or one or more neighbor cells, and serving cells and/or neighbor cells associated with the VMs that are operating in the suspended state. In this regard, the serving cells and/or the neighbor cells associated with VMs operating in the suspended state may be added as neighbor cells for the VM 340 that is operating in the active state.

The VM 340 may be operable to measure the signal strength on its own serving cell, and the serving cells and the neighbor cells that are associated with the VMs operating in the suspended state. The cell signal strength measurements may be utilized to determine cell quality of corresponding cells. For example, a cell corresponding to the strongest cell signal strength measurement may be selected or picked as the best cell associated with the multi-SIM and multi-standby communication device 200 for tracking cell timing information, for example. The VM 340 may be operable to track or retrieve cell information such as, for example, cell timing information, associated cellular frequencies, cell identity information and/or cell selection results, for its own serving cell and/or one or more neighbor cells, and each of the added serving cells and neighbor cells associated with one or more remaining ones of the plurality of VMs, for example, the VM 350, operating in the suspended state based on the corresponding cell signal strength measurements. In instances where the VM 340 returns to an idle state from the active state, the single radio resource unit 370 may release radio resources that are previously assigned to the VM 340.

The VMC 360 may then resume the suspended VMs such as the VM 350 for normal idle mode activities. In this regard, the VMC 360 may coordinate or manage operations of the single radio resource unit 370 such that the single radio resource unit 370 may synchronize to the serving cells associated with the suspended VMs. The synchronization may be performed in an order determined by the cell timing information that is tracked by the VM 340. In instances where a serving cell associated with a suspended VM such as the VM 350 is still available in the tracked timing information, the VM 350 may bypass cell selection or cell reselection to achieve a fast cell recovery. More specifically, the VM 350 may directly camp on the associated serving cell without performing cell selection or cell reselection. Otherwise, the VM 350 needs to perform cell selection or reselection in order to identify a suitable cell to camp on. In this regard, the VM 350 may selectively perform cell selection/reselection based on tracked cell information such as cell signal strength measurements, cell timing information, associated cellular frequencies, cell identity information and/or cell selection results, for a fast cell selection/reselection. For example, the VM 350 may perform cell selection/reselection for cells with high cell quality and/or for cells placed on particular cellular frequencies.

Other embodiments of the invention may provide a non-transitory computer readable medium and/or storage medium, and/or a non-transitory machine readable medium and/or storage medium, having stored thereon, a machine code and/or a computer program having at least one code section executable by a machine and/or a computer, thereby causing the machine and/or computer to perform the steps as described herein for a fast cell recovery on suspended virtual modems within a multi-SIM multi-standby communication device.

Accordingly, the present invention may be realized in hardware, software, or a combination of hardware and software. The present invention may be realized in a centralized fashion in at least one computer system, or in a distributed fashion where different elements are spread across several interconnected computer systems. Any kind of computer system or other apparatus adapted for carrying out the methods described herein is suited. A typical combination of hardware and software may be a general-purpose computer system with a computer program that, when being loaded and executed, controls the computer system such that it carries out the methods described herein.

The present invention may also be embedded in a computer program product, which comprises all the features enabling the implementation of the methods described herein, and which when loaded in a computer system is able to carry out these methods. Computer program in the present context means any expression, in any language, code or notation, of a set of instructions intended to cause a system having an information processing capability to perform a particular function either directly or after either or both of the following: a) conversion to another language, code or notation; b) reproduction in a different material form.

While the present invention has been described with reference to certain embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the present invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the present invention without departing from its scope. Therefore, it is intended that the present invention not be limited to the particular embodiment disclosed, but that the present invention will include all embodiments falling within the scope of the appended claims. 

1. A method for communication, the method comprising: in a multiple-subscriber identity module (multi-SIM) multi-standby communication device comprising a single radio resource unit that is shared by a plurality of virtual modems: when a first virtual modem of said plurality of virtual modems is operating in an active state and one or more remaining ones of said plurality of virtual modems are operating in a suspended state, monitoring, by said first virtual modem, a serving cell and/or one or more neighbor cells associated with said first virtual modem, and one or more serving cells and/or one or more neighbor cells which are associated with a corresponding one of said one or more remaining ones of said plurality of virtual modems that are operating in said suspended state.
 2. The method according to claim 1, comprising adding said one or more serving cells and/or said one or more neighbor cells associated with said one or more remaining ones of said plurality of virtual modems operating in said suspended state as neighbor cells for said first virtual modem operating in said active state.
 3. The method according to claim 2, comprising measuring signal strength on said serving cell and/or said one or more neighbor cells associated with said first virtual modem operating in said active state and said added one or more serving cells and/or said added one or more neighbor cells associated with said one or more remaining ones of said plurality of virtual modems operating in said suspended state.
 4. The method according to claim 2, comprising determining cell quality, when needed, for said serving cell and/or said one or more neighbor cells associated with said first virtual modem operating in said active state and said added one or more serving cells and/or said added one or more neighbor cells associated with said one or more remaining ones of said plurality of virtual modems operating in said suspended state.
 5. The method according to claim 3, comprising tracking timing information for each of said serving cell and/or said one or more neighbor cells associated with said first virtual modem operating in said active state and said added one or more serving cells and/or said added one or more neighbor cells associated with said one or more remaining ones of said plurality of virtual modems operating in said suspended state based on said measurement.
 6. The method according to claim 5, comprising synchronizing to said added one or more serving cells based on said tracked timing information when said one or more remaining ones of said plurality of virtual modems operating in said suspended state transition to an idle state.
 7. The method according to claim 6, comprising determining a cell order based on said tracked timing information for said synchronizing.
 8. The method according to claim 7, comprising synchronizing to each of said added one or more serving cells based on said determined cell order.
 9. The method according to claim 6, comprising if corresponding timing information for said added one or more serving cells is available in said tracked timing information, bypassing cell selection or cell reselection.
 10. The method according to claim 6, comprising if corresponding timing information for said added one or more serving cells is not available in said tracked timing information performing cell selection or cell reselection during said synchronization based on tracked cell information.
 11. A system for communication, the system comprising: one more processors and/or circuits for use in a multiple-subscriber identity module (multi-SIM) multi-standby communication device comprising a single radio resource unit that is shared by a plurality of virtual modems, said one or more processors and/or circuits being operable to: when a first virtual modem of said plurality of virtual modems is operating in an active state and one or more remaining ones of said plurality of virtual modems are operating in a suspended state, monitor, by said first virtual modem, a serving cell and/or one or more neighbor cells associated with said first virtual modem, and one or more serving cells and/or one or more neighbor cells which are associated with a corresponding one of said one or more remaining ones of said plurality of virtual modems that are operating in said suspended state.
 12. The system according to claim 11, wherein said one or more processors and/or circuits being operable to add said one or more serving cells and/or one or more neighbor cells associated with said one or more remaining ones of said plurality of virtual modems operating in said suspended state as neighbor cells for said first virtual modem operating in said active state.
 13. The system according to claim 12, wherein said one or more processors and/or circuits being operable to measure signal strength on said serving cell and/or said one or more neighbor cells associated with said first virtual modem operating in said active state and said added one or more serving cells and/or said added one or more neighbor cells associated with said one or more remaining ones of said plurality of virtual modems operating in said suspended state.
 14. The system according to claim 13, wherein said one or more processors and/or circuits being operable to determine cell quality, when needed, for said serving cell and/or said one or more neighbor cells associated with said first virtual modem operating in said active state and said added one or more serving cells and/or said added one or more neighbor cells associated with said one or more remaining ones of said plurality of virtual modems operating in said suspended state.
 15. The system according to claim 13, wherein said one or more processors and/or circuits being operable to track timing information for each of said serving cell and/or said one or more neighbor cells associated with said first virtual modem operating in said active state and said added one or more serving cells and/or said added one or more neighbor cells associated with said one or more remaining ones of said plurality of virtual modems operating in said suspended state based on said measurement.
 16. The system according to claim 15, wherein said one or more processors and/or circuits being operable to synchronize to said added one or more serving cells based on said tracked timing information when said one or more remaining ones of said plurality of virtual modems operating in said suspended state transition to an idle state.
 17. The system according to claim 16, wherein said one or more processors and/or circuits being operable to determine a cell order based on said tracked timing information for said synchronizing.
 18. The system according to claim 17, wherein said one or more processors and/or circuits being operable to synchronize to each of said added one or more serving cells based on said determined cell order.
 19. The system according to claim 16, wherein said one or more processors and/or circuits being operable bypass cell selection or cell reselection if corresponding timing information for said added one or more serving cells is available in said tracked timing information.
 20. The system according to claim 16, wherein said one or more processors and/or circuits being operable to perform cell selection or cell reselection during said synchronization based on tracked cell information if corresponding timing information for said added one or more serving cells is not available in said tracked timing information. 